Remember silence? Yeah, me either. Even in remote locales like the beaches of Thailand[9] or my own exurb backyard, noise from jets is an ever-present disturbance. In London, it’s apparently so bad, that city’s residents are calling it a threat to mental health[10]. Constant loud engines, honks, alarms and sirens: certainly not something with which our ancestors[11] had to deal. I’m sure someone’s going to tell the Brits they’re being pansies. But I’m inclined to think that persistent, low-level stress of this sort is more serious than we know.